1. Field of the Invention
The present invention relates to a screw and, more particularly, to a screw with a spiral continual groove in which residues can be held.
2. Description of the Related Art
A large amount of wood or compound wooden materials mixed and compressed from plastic resin and wood chips are used to produce wooden articles for furniture, decoration and construction, and screws are often used in connecting wooden articles together. A conventional screw generally includes a shank and at least one thread formed on the shank, so that the screw can be screwed into the articles which need to be fastened or interlocked. Furthermore, in order to enhance the speed of screwing the screw into the articles to be fastened, a design with slots disposing in the shank or crests of the thread for collecting or receiving chips or residues is already proposed. More specifically, chips, wooden chips for example, are produced when the screw is screwed into the articles to be assembled, and the slots can be used for receiving the chips so that the chips will not obstruct the process of screwing the screw into the articles, allowing rapid insertion of the screw into the articles and preventing disintegration of the materials of the articles. However, chips or residues held in the slots in the shank or the crest are limited and accumulate in an upper section of a screw mostly, decelerate a process of the screw being driven in the article, and even inflate or break the article.
Taiwan Utility Model No. M373974 discloses a screw with chip removal flutes. The screw includes two symmetric spiral chip removal flutes formed on a periphery of a self-drilling portion for removing residues from the screw driven in a wood article. However, each chip removal flute which is wide and has more circles on a screw shank (even on the whole shank) allows threads and the article to occlude ineffectively, reducing binding capacity of the screw. Furthermore, the chip removal flutes decrease strength of the screw and make the screw driven in the article break easily.